Back to EveryPatent.com
| United States Patent |
6,072,389
|
|
Strasburger
|
June 6, 2000
|
Brake adjustment monitor device for automotive vehicles
Abstract
The brake adjustment monitor has a pull or breakaway switch having an
activation pin as part thereof which activation pin is attached to the
push rod and slack adjustment arm assembly of an air brake system by a
cable. The switch itself is attached to an existing bolt screw or like
attachment device on the air chamber assembly of the brake. When the
switch and cable are installed on a brake assembly the cable is adjusted
to a length to pull the activation pin to operate the switch when the push
rod has traveled a predetermined distance. This distance, as is known in
the art, is an indication of brake wear or misadjustment. A number of bulb
indicators with or without sound indicators may be mounted on a trailer or
motorized vehicle and electrical connected to indicate to an operator the
switch activation.
| Inventors:
|
Strasburger; Bill (P.O. Box 2104, Yorba Linda, CA 92885-1304)
|
| Appl. No.:
|
400664 |
| Filed:
|
September 20, 1999 |
| Current U.S. Class: |
340/454; 116/208; 340/453 |
| Intern'l Class: |
B60Q 001/00 |
| Field of Search: |
340/454,453
188/1.11
92/512
116/208
|
References Cited
U.S. Patent Documents
| 4945818 | Aug., 1990 | Ware | 92/5.
|
| 5140932 | Aug., 1992 | Goldfein et al. | 116/208.
|
| 5285190 | Feb., 1994 | Humphreys et al. | 340/453.
|
| 5320198 | Jun., 1994 | Hoyt et al. | 188/1.
|
| 5358075 | Oct., 1994 | Jarzombek | 188/1.
|
| 5433296 | Jul., 1995 | Webberley | 188/1.
|
| 5450930 | Sep., 1995 | Martens et al. | 188/1.
|
| 5474154 | Dec., 1995 | Coale | 188/1.
|
| 5649469 | Jul., 1997 | Pierce | 92/5.
|
| 5934415 | Aug., 1999 | Preston et al. | 188/1.
|
Primary Examiner: Wu; Daniel J.
Assistant Examiner: Nguyen; Tai T.
Attorney, Agent or Firm: Beech; Dennis W.
Claims
I claim:
1. A brake adjustment monitor device installation with an automotive
vehicle air brake system comprising:
a switch having output means for communication to an operator that the
switch has been activated and the switch attachable to an air chamber
assembly by a means for attachment;
an activation pin operatively engaged with the switch and having a cable at
one end attached thereto;
the cable at an opposite end attachable to an assembly of a push rod and a
slack adjustment arm of an air brake system by a cable means for
attachment such that when movement of the push rod has reached a
predetermined distance the cable will pull the activation pin a sufficient
distance to activate the switch.
2. The device as in claim 1 wherein the means for communication is the
activation pin pulled from the switch and hanging under the force of
gravity at the end of the cable.
3. The device as in claim 1 wherein the means for communication is a
plurality of electrical leads having at least one lead connected to a bulb
and to a power supply and a second lead connected to an electrical ground.
4. The device as in claim 3 wherein the power supply is independent of the
automotive vehicle power supply.
5. The device as in claim 3 wherein at least one of the bulbs is attachable
to a front of a vehicle trailer for operator viewing by means of a rear
view mirror.
6. The device as in claim 1 wherein the means for attachment to the air
chamber assembly is an angle bracket attached to an existing attachment
device and the switch having a bracket for attachment to the angle
bracket.
7. The device as in claim 1 wherein the cable means for attachment is an
existing attachment device of the slack adjustment arm.
Description
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to devices used to monitor the brake wear and
adjustment on vehicles employing air brake systems, such as, trucks,
tractor trailers, buses and the like. The new device provides a simple
means to install a monitoring system for monitoring each of the brakes of
a vehicle.
2. Description of Related Art
There are currently published and known systems in the art which typically
use a permanent magnet as a basis for measuring brake wear wherein the
magnet is mounted to a rod which moves when the air brakes are activated.
For example, the push rod of a brake system travels a certain distance
when air pressure is applied to an air chamber assembly which distance is
a function of brake wear and adjustment of the brake assembly. A
magnetically activated switch is used in cooperation with the magnet such
that if the push rod moves a certain distance the switch is activated to
signal that the brake must be attended to for repair. Examples of such
systems are disclosed in U.S. Pat. No. 4,757,300 and 4,855,712.
Other attempts to use measured motion of the push rod, other brake rods and
rotation of the connection between the push rod and shock adjuster arm
have also been proposed. In U.S. Pat. No. 5,689,231, a transducer engaged
with a clevis pin monitors rotation relative to the push rod and shock
adjuster arm to provide indication when brake repair may be necessary.
The present invention provides a simple mechanism for monitoring brake wear
and adjustment by using a cable attached to a pull or breakaway switch to
signal when the air brake system push rod has traveled beyond a
predetermined distance relative to the air chamber. This device is
relatively easy to install on existing brakes using for attachment points
existing threaded bolts, screws and the like. The pull or breakaway switch
may be a rugged self contained unit with two electrical leads and have a
simple cable attachment. No devices need to be mounted to the push rod
obviating the concern for proper location of such units.
SUMMARY OF THE INVENTION
One object of the present invention is simple, straight forward attachment
of the brake monitor device to existing or new air brake systems to signal
the event of an air brake rod movement beyond a predetermined distance.
Another object is to allow such brake monitoring device to operate using
an existing vehicle power source or using a power source independent of
the vehicle. A further object is to provide indication of monitoring
device activation on separate trailers as well as on motorized vehicles.
In accordance with the description presented herein, other objectives of
this invention will become apparent when the description and drawings are
reviewed.
BRIEF DESCRIPTION OF THE DRAWING
FIG. 1 illustrates a perspective view of a pull or breakaway switch.
FIG. 2 illustrates a schematic view of the switch attached to a bulb
warning system using an independent power source.
FIG. 3 illustrates a schematic representation of the monitoring device
having a plurality of bulb warning indication locations.
FIG. 4 illustrates a pull type switch and cable in the monitor position.
FIG. 5 illustrates a pull type switch and cable in the activated position.
FIG. 6 illustrates a breakaway type switch and cable in the monitoring
position.
FIG. 7 illustrates a breakaway switch and cable in the activated position.
FIG. 8 illustrates the brake adjustment monitor device installed with an
air brake system.
FIG. 9 illustrates the brake adjustment monitor device installed with a
spring brake automatic air break out system as currently required on at
least one axle of a vehicle.
DESCRIPTION OF THE PREFERRED EMBODIMENT
The brake adjustment monitor device comprises a pull or breakaway switch
attached to the vehicle air brake chamber structure and having a cable
attached to the rods or slack adjustment arm of a vehicle air brake
system. The cable length when installed is adjusted to activate the switch
when the air brake rod has traveled a predetermined distance. The
predetermined distance is an indication that in air brake systems the
brake pads and drum (25) have reached a condition in which the brakes will
soon no longer engage or function. The switch is electrically connected to
one or more bulb indicators and if desired a sound signaling device.
Referring to FIGS. 1 through 3, the monitoring device has a switch (1) with
electrical leads (2) and cable (3). The electrical leads (2) are in
communication with one or more bulbs (4) for indicating the switch (1)
open or closed status. The bulb (4) warning indicators may be on the rear
(5) of a trailer (6) or motorized vehicle (7), on the front (8) so as to
be viewed in the drivers rear view mirrors (9) and/or mounted with the
vehicle dash board indicators (10). Obviously these bulbs (4) may be
augmented with a warning sound device such as a buzzer (not shown).
For any vehicle, but in particular for a trailer as illustrated in FIG. 3,
the monitoring device may use a power supply (11) independent of the
vehicle standard electrical power system such as brake light system or
ignition switch power system. This provides added safety margin as the
monitoring device does not depend on proper vehicle electrical connection
to provide warning of brake wear. Of course the monitoring device may be
connected to the vehicle electrical power system as is commonly
understood. By placing bulb (4) warning indicators on the front (8) of a
trailer, an operator may be warned of brake wear even if the vehicle to
trailer electrical system has not been properly connected.
Referring to FIGS. 4 through 9, the switch (1) and cable (3) are
illustrated in both monitoring and activated conditions and are shown
attached to vehicle brake assemblies (12). In the preferred embodiment the
switch (1) has bracket (13) with aperture (14). An angle bracket (15) is
attached to an existing threaded bolt (16) on the air brake air chamber
assembly (17). The bracket (13) is then attached, either fixedly or
rotatably, to the angle bracket (15).
The cable (3) on one end is attached to an activation pin (18) of the
switch (1) and on the opposite end to an existing bolt, screw, pin or the
like of the slack adjuster arm (19) of the brake assembly (12). When the
cable (3) is installed, its length is adjusted to cause it to pull the
activation pin (18) should the brake push rod (20) travel more than a
predetermined distance when the vehicle operator depresses the brake
peddle. This distance of travel is based on brake type to indicate wear on
the brake has reached a predetermined point such that brake failure is
imminent.
In operation with the brakes not engaged the cable (3) may have a slack as
illustrated in FIGS. 4, 6, 8 and 9. When the brakes are operated by the
vehicle operator, the diaphragm in the air chamber assembly (17) urges the
attached push rod (20) outwards which in turn moves the slack adjuster arm
(19). This brake assembly operation causes the cable (3) to pull against
the force of activation pin (18) which with sufficient movement will cause
the cable (3) to become taut. If the travel of the push rod (20) reaches
the predetermined distance of travel, the switch (1) is activated by the
distance of movement of the activation pin (18) as illustrated in FIG. 5
or the release of the activation pin (18) as illustrated in FIG. 7. In the
case of FIG. 7 a visual indication of wear is provided with the dangling
cable (3) and activation pin (18). In either configuration the activation
pin (18) movement causes the switch (3) to signal push rod (20) movement
the predetermined distance to warn of needed brake service.
While in the preferred embodiment the cable (3) has been described as
attached to an existing location on the slack adjustment arm (19) as the
simplest installation, obviously the cable (3) may have means for
attachment such as to the push rod (20) itself. So long as the cable (3)
is drawn tout by the movement of the push rod (20) relative to the air
chamber assembly (17) the brake monitoring switch (1) and cable (3) may be
attached in the most convenient manner depending on the particular brake
system.
While the invention has been particularly shown and described with respect
to the illustrated and preferred embodiments thereof, it will be
understood by those skilled in the art that the foregoing and other
changes in form and details may be made therein without departing from the
spirit and scope of the invention.
Top